Eye Surface Research Articles

Is it time for a moratorium on the use of benzalkonium chloride in eyedrops?

Is it time for a moratorium on the use of benzalkonium chloride in eyedrops?

Neonatal Opioid Withdrawal Syndrome in Mice: Acute Molecular and Long‐Term Behavioral Consequences

Populations affected by the ongoing opioid epidemic include pregnant women and their offspring. Infants exposed to opioids in utero are at risk of developing Neonatal Opioid Withdrawal Syndrome (NOWS), a combination of somatic withdrawal symptoms including high pitched crying, sleeplessness, irritability, and potentially seizures. Confounding environmental factors and difficulty in conducting longitudinal clinical studies have made it challenging to elucidate the long‐term consequences of NOWS. In order to investigate the molecular mechanisms and long‐term effects of NOWS, we have developed a mouse model of opioid exposure and withdrawal that encompasses the developmental equivalent of all three trimesters of the human pregnancy. Female mice are implanted with morphine minipumps (10 mg/kg/day) before mating, ensuring that pups are exposed to morphine in utero for the entirety of embryonic development. Mice are then given twice daily morphine injections (10 mg/kg/day, SC) for post‐natal days 1‐14. Mice are tested for developmental milestones during this period, including eye opening, extinguishing pivoting, surface righting, and forelimb grasp. Following the final morphine injection withdrawal behaviors were measured by ultrasonic vocalizations, 55°C hotplate analgesia latency, and somatic withdrawal signs. After reaching adulthood, mice were tested for changes in affective behavior (elevated zero maze, tail suspension test and learned helplessness), opioid response (conditioned place preference and intravenous self‐administration), social behavior (three‐chamber social behavior test), and sleep patterns. Mice exposed to this paradigm show delayed latency to reach developmental milestones and acute withdrawal phenotypes. In adulthood, social behavior and sleep patterns were affected in a sex‐dependent manner, while affective behavior and opioid response was unchanged. Bulk RNA sequencing of mice at post‐natal day 1 revealed changes in gene expression related to synapse development and function, the GABAergic system, and mitochondrial function. These transcriptome changes may underlie the behavioral long‐term effects of NOWS.

Model Eye Pictures can Lay the Foundation for Pictures Observed by Patients having Cataract Surgery while Simulation

Aim: The photographs of a model eye during the fake waterfall are to be evaluated by medical treatment.
 Methodology: This study was performed as a study in a research institution and a case procedure was carried out. Our current research was conducted at People Medical College Hospital, Nawabshah from April 2020 to March 2021. In the "front office" of a model eye, the iced rear surface was inserted with a flawed fogged focus, an acceptable intraocular focal point or an I/A tip. During the replicated Waterfall treatment, video pictures were collected from the back surface of the model eye. Before the waterfall surgery, 26 patients saw the video pictures and post-operatively rated their visual impressions.
 Results: View from behind were pictures of the movable focal parts, the I/A tip and the IOL add-on. The image via the opiated focus point and the IOL has been the light of the meticulous enlargement lens from behind without moving objects. However, after IOL added, pictures of the tiny and working space were switched off from behind by the light of the magnifying equipment. 70% of patients reported the visual feel of shifting focal components as video cuts and 58%. The overwhelming majority of patients advised that the film before their intended medical operation should be viewed.
 Conclusion: The model eye can re-enable visual insight for patients throughout the medical treatment for a waterfall. The preoperative view of the video pictures might aid to loosen the sufferers during the treatment.

Mucoadhesive PLGA Nanospheres and Nanocapsules for Lactoferrin Controlled Ocular Delivery.

Background: the present work describes the preparation, characterization and optimization of eight types of PLGA-based nanosystems (nanospheres and nanocapsules) as innovative mucoadhesive drug delivery systems of lactoferrin, in order to achieve a preclinical consistent base as an alternative pharmacological treatment to different ocular syndromes and diseases. Methods: All different nanoparticles were prepared via two modified nanoprecipitation techniques, using a three-component mixture of drug/polymer/surfactant (Lf/PLGA/Poloxamer), as a way to overcome the inherent limitations of conventional PLGA NPs. These modified polymeric nanocarriers, intended for topical ophthalmic administration, were subjected to in vitro characterization, surface modification and in vitro and in vivo assessments. Results: An appropriate size range, uniform size distribution and negative ζ potential values were obtained for all types of formulations. Lactoferrin could be effectively included into all types of nanoparticles with appropriate encapsulation efficiency and loading capacity values. A greater, extended, and controlled delivery of Lf from the polymeric matrix was observed through the in vitro release studies. No instability or cytotoxicity was proved for all the formulations by means of organotypic models. Additionally, mucoadhesive in vitro and in vivo experiments show a significant increase in the residence time of the nanoparticles in the eye surface. Conclusions: all types of prepared PLGA nanoparticles might be a potential alternative for the topical ophthalmic administration of lactoferrin.

Designing Fish Optic Mobile Application for Fish Disease Identification

The signs and symptoms of fish disease can be traced by checking on the eye surface which is the cornea of fisheye. The Fish Optic mobile application aims to help students study the fisheye anatomy and to trace the symptoms of diseases on fish. The Fish Optic user mobile application uses Human-Centered System Development Life Cycle (HCSDLC) which consists of four phases which are project selection and planning, analysis, design and implementation. As HCSDLC emphasizes on user involvement throughout all phases, an interview was conducted, and a post task walkthrough was performed. User Acceptance Test formative evaluation was then conducted by distributing questionnaire. Some recommendations are also discussed for future works to improve and refine the design of the Fish Optic mobile application to enhance user experience. It can be concluded that using HCSDLC method throughout the design of Fish Optic mobile application contributes to a well-defined systems requirement to support user needs and to accommodate the lack of human understanding that frustrates users in their daily routines.

Eye surface infrared thermography usefulness as a noninvasive method of measuring stress response in sheep during shearing: Correlations with serum cortisol and rectal temperature values

During shearing, animals’ welfare is adversely affected and acute stress occurs. Once animal perceives a threat, it develops behavioral, autonomic, endocrine or immune responses to maintain homeostasis. This study aimed to investigate the usefulness of eye temperature assessment by infrared thermography (IRT) to evaluate acute stress response in sheep undergoing a shearing procedure. From each animal, blood sampling, rectal and eye temperature assessment were performed before shearing (TPRE), 5 (TPOST5) and 60 (TPOST60) minutes after the end of shearing procedure. On blood samples the serum cortisol concentrations were evaluated. Rectal temperature (TRECTAL) was measured using a digital thermometer. Thermographic acquisitions of eye temperature were performed from the eye total area (TEYE) and from three regions of interest (lateral canthus, TROI-1; central cornea, TROI-2; medial canthus, TROI-3). One-way analysis of variance showed a significant increase of serum cortisol concentration, TRECTAL, TEYE and TROI-3 (p < 0.001). Serum cortisol was positively correlated with TRECTAL and TROI-3 at TPOST5 and TPOST60. TRECTAL resulted positively correlated with TROI-3 at TPRE, TPOST5 and TPOST60. Agreement between TRECTAL and each eye temperature considered (TEYE, TROI-1, TROI-2, TROI-3) has been shown by Bland–Altman plots at each time point of monitoring period. The findings obtained in the current survey suggest that the medial canthus is the most suitable region for eye temperature measurement to asses stress response in animals. Moreover, this study highlighted the usefulness of IRT as an immediate and non-invasive physiological measure to assess stress response in sheep.

Thermosensitive Tri-Block Polymer Nanoparticle-Hydrogel Composites as Payloads of Natamycin for Antifungal Therapy Against Fusarium Solani.

PurposeFusarium Solani is the principal pathogen associated with fungal keratitis. As a sensitive drug to F. Solani, natamycin (NAT) was limited by the poor penetration and low bioavailability in clinical application. The aim of this study was to develop a new type of tri-block polymer nanoparticle-gel complex (Gel@PLGA-PEI-PEG@NAT) for delivering NAT and evaluate its physicochemical properties, antifungal activity, safety, penetrability, adhesion, and efficacy in treating fungal keratitis.MethodsPLGA-PEI-PEG@NAT was prepared and characterized with a nano-particle size analyzer, transmission electron microscopy (TEM), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR). The minimum inhibitory concentration (MIC), cytotoxicity, penetrability of NAT (Natacyn® 5% ophthalmic suspension; Alcon) and PLGA-PEI-PEG@NAT with different concentrations were assessed. The eye surface retention time, ocular irritation, and curative effect of the NAT ophthalmic suspension and Gel@PLGA-PEI-PEG@NAT on a rabbit fungal keratitis model were evaluated.ResultsPLGA-PEI-PEG@NAT had a particle size of 150 nm, a positive surface charge, and a sustained-release effect. The MIC for F. Solani was 2 μg/mL. A cytotoxicity test and ocular irritation test showed that PLGA-PEI-PEG@NAT and Gel@PLGA-PEI-PEG@NAT had good biocompatibility and no obvious irritation for rabbit corneas. Penetration experiments confirmed that PLGA-PEI-PEG@NAT can successfully enter corneal epithelial cells and through the cornea to enter the anterior chamber. Compared with NAT ophthalmic suspension, Gel@PLGA-PEI-PEG@NAT had stronger cornea permeation at the same concentration. The therapeutic effect and precorneal retention ability of the NAT ophthalmic suspension and Gel@PLGA-PEI-PEG@NAT on the fungal keratitis rabbit model were compared. Gel@PLGA-PEI-PEG@NAT achieved a better therapeutic effect at a lower drug concentration, and its eye surface retention time was significantly longer than that of the NAT ophthalmic suspension.ConclusionGel@PLGA-PEI-PEG@NAT was shown to be a safe and effective nanodrug delivery system for NAT. It has great potential to improve the cure rate of fungal keratitis, reduce the administration frequency during the treatment process, and improve patient compliance.

Host-trailing satellite flight behaviour is associated with greater investment in peripheral visual sensory system in miltogrammine flies

Insect sensory systems are the subjects of different selective pressures that shape their morphology. In many species of the flesh fly subfamily Miltogramminae (Diptera: Sarcophagidae) that are kleptoparasitic on bees and wasps, females perch on objects close to the host nests and, once a returning host is detected, they follow it in flight at a fixed distance behind until reaching the nest. We hypothesized that such satellite (SAT) flight behaviour, which implies a finely coordinated trailing flight, is associated with an improved visual system, compared to species adopting other, non-satellite (NON-SAT) strategies. After looking at body size and common ancestry, we found that SAT species have a greater number of ommatidia and a greater eye surface area when compared to NON-SAT species. Ommatidium area is only affected by body size, suggesting that selection changes disproportionately (relative to body size variation) the number of ommatidia and as a consequence the eye area, instead of ommatidium size. SAT species also tend to have larger ocelli, but their role in host-finding was less clear. This suggests that SAT species may have a higher visual acuity by increasing ommatidia number, as well as better stability during flight and motion perception through larger ocelli. Interestingly, antennal length was significantly reduced in SAT species, and ommatidia number negatively correlated with antennal length. While this finding does not imply a selection pressure of improved antennal sensory system in species adopting NON-SAT strategies, it suggests an inverse resource (i.e. a single imaginal disc) allocation between eyes and antennae in this fly subfamily.

Smartphone-based corneal topography with null-screens.

To measure the shape of the fast corneal surface of the human eye, we propose the design and characterization of a compact corneal topographer using the capabilities of a smartphone. The performance evaluation of the compact corneal topographer includes the calculation and compensation of the distortion introduced by the smartphone lens used to acquire the images and the evaluation of a reference surface. To demonstrate the feasibility of our proposal, we performed surface topography measurements on some human corneas and compared the results with those obtained by a commercial corneal topographer. We showed that the results obtained with our algorithms were consistent with other methods that analyze the corneal surface.

Uso da ceratectomia superficial lamelar central automatizada no tratamento das ceratites superficiais pigmentares crônicas em cães

ABSTRACT Pigmentary superficial keratitis (PSK) is a chronic corneal disorder with different causes, which may include immune-mediated diseases and reactions to ultraviolet rays. This study aimed to evaluate the use of automated central lamellar superficial keratectomy (ACLSK) in the treatment of chronic pigmentary superficial keratitis (CPSK) in dogs. We enrolled 24 animals with CPSK and loss of visual function even after clinical treatment with preserved post-corneal transparent media, and the potential for recovery of visual function after surgical treatment. The microkeratome was positioned on the eye surface, and the central corneal lamellae were obtained after translation. With ACSLC, 21 animals (87.5%) recovered their visual function. In 3 animals (12.5%), the formation of granuloma and posterior central leukoma in the cornea compromised the transparency of the visual axis. This study concludes that ACLSK is a viable surgical alternative for the restoration of visual function in dogs with severe PSK, thus improving their quality of life. The short execution time of this procedure reduces the costs and anesthetic risks.

Mice with disrupted canonical phototransductive pathways retain robust VEP responses under light-adapted conditions

The Gnat1−/−, Gnat2−/−, Opn4−/− triple knockout (TKO) mouse line, lacking alpha transducins in rods and cones and melanopsin in ip-RGCs, is generally considered to be blind. Previous studies using electroretinograms have found that these animals retain residual light sensitivity only under dark-adapted conditions. Here, we show cortical responses to light (visual evoked potentials (VEPs)) recorded from TKO mice under light-adapted conditions. VEPs were recorded from C57BL/6J mice (n=6) and TKO mice (n=5) via 50ms flashes over 4 log units of intensity, with maximal illuminance of 44.3 mW/cm∧2 at the surface of the contralateral eye (λcenter = 530nm).

Corneal Stromal Abscess in a Dog

ABSTRACTBackground: The eye is an important sense organ responsible for sight. The cornea is the outermost of many eye layers, being predisposed to several lesions, some of them being frequent in small animal clinics meanwhile others are unusual and seldom reported in specialized literature. The stroma abscess is a common condition in horses, but atypical in dogs, it's a condition in which a microperforation in the corneal epithelium allows microorganisms or a foreign body to penetrate the corneal stroma, and those become inside the cornea after a re-epithelialization, producing an intense inflammatory response. Therefore, this case reports a case of deep stromal abscess in a Shih Tzu dog.Case: A 4-year-old female Shih Tzu, weighing 4.6 kg, was submitted to ophthalmic examination in which the left eye presented an opaque yellowish-white protruding structure located on the right side, in the center of the cornea (3 o´clock position), bulbar and palpebral conjunctival hyperemia and congestion, chemosis, blepharospasm, and a moderate amount of mucous discharge. The clinical diagnosis was stromal abscess with reflex uveitis. A differential diagnosis should include conditions affecting the anterior part of the cornea, such as an epithelial inclusion cyst and a corneal ulcer. The inclusion cyst, contrarily to the corneal abscess, doesn't cause pain, meanwhile, the corneal ulcer was ruled out by the Fluorescein Staining Test. The recommended treatment was surgical, through lamellar keratectomy, followed by overlapping pedicled conjunctival graft and third eyelid flap. In association with the surgical treatment, oral antibiotics, anti-inflammatory, and opioids, plus topical antibiotics and autologous serum eye drop. Seventy days post-surgery, the previously observed inflammatory signs were no longer present. In the conjunctival graft insertion site perpetuated a scar leucoma with few blood vessels. The therapy was proven effective in solving the stromal abscess and in visual maintenance. Despite the located opacity due to leucoma, it barely causes any impairment, once its lateral position won't impact the central vision, which is more important to predator species than the peripheral vision.Discussion: Stromal abscess is a pathological condition in which an initial perforating corneal injury leads to a rupture of the epithelial barrier, allowing the access of bacterial, fungus, or foreign bodies of organic nature. The morbidity is more frequent in horses, but this report shows that although uncommon, stromal abscesses can occur in dogs. The diagnosis was achieved by an analysis of the clinical history and findings. Conditions that affect the anterior cornea must be among differential diagnoses. Treatment aims for the removal of infectious material with debridement and curetting of the stroma, by performing the lamellar keratoplasty technique, which produces a corneal wound. The implementation of a pedicled conjunctival graft allows, the influx of growth factors, active replication of stromal collagen by fibroblasts, and direct arrival of antibiotics through the blood supply to the exposed portion of the cornea. The third eyelid flap is questioned by some authors, once it complicates the post-op follow up, and hinder the topical therapy from directly reaching the eye surface. Autologous serum: A blood-derived product often used to control corneal melting. The Federal Medicine Board determined that autologous serum eyedrops therapy has been scientifically proven effective, being used worldwide in the treatment of severe eye surface conditions. In Veterinary, studies also demonstrated that autologous serum can improve improve the corneal re-epithelialization in dogs. Keywords: autologous serum, keratectomy, ophthalmology, veterinary.Título: Abscesso estromal em córnea de cãoDescritores: soro autólogo, ceratectomia, oftalmologia, veterinária.

Does Orthokeratology Wearing Affect the Tear Quality of Children?

Orthokeratology is currently known as one of the most effective methods of myopia control in the process of rapid deterioration of the global myopia prevalence. As orthokeratology is widely used, it is necessary to evaluate its complications reasonably and accurately. Eye surface problems in children, such as dry eyes, have received increasing attention. At present, there is no conclusive evidence on how orthokeratology affects the ocular surface, especially the tears. To our knowledge, this is the first study to explore the relationship between orthokeratology lenses and tears through meta-analysis. However, it is still challenging to get a convincing conclusion and a higher level of evidence in this meta-analysis. Reasons for this include limitation of study design, lack of clarity on important confounding factors, lack of appropriate statistical tools, and other biases. This paper will analyze the dilemma existing in the current research from different perspectives to provide meaningful information for future studies in this field.

A novel ophthalmic latanoprost 0.005% nanoemulsion: a cytotoxicity study.

Benzalkonium chloride (BAK), the most commonly used preservative in anti-glaucoma eye drops, inflicts damage to the ocular surface. A novel anti-glaucoma formulation that avoids the use of BAK has been developed. The aim of this study was to evaluate the cytotoxicity of this formulation and to compare it with an ophthalmic solution containing BAK. Two different latanoprost eye drops were used: one ophthalmic solution (LSc) containing BAK 0.02% and one ophthalmic nanoemulsion (LNe) with a soft preservative (potassium sorbate 0.18%). Human epithelial conjunctival cells were incubated for 15, 30, and 60min with either LSc or LNe. The cytotoxicity was determined by MTT assay. Cell death was measured by flow cytometry using annexin V-FITC and propidium iodide. The values of cell viability and proliferation obtained from cells exposed to LNe were between 80 and 90% relative to the control group, whereas values obtained from cells exposed to LSc were around 30% at all study times (p < 0.05 at 15 and 30min; p < 0.01 at 60min). The percentage of viable cells decreased significantly when cells were incubated with LSc compared with cells incubated with LNe at all the study times, while the percentage of cells in late apoptosis/necrosis increased significantly in cells exposed to LSc compared to LNe. The new latanoprost nanoemulsion is significantly less cytotoxic on human conjunctival cells than LSc. These results suggest that the new formulation might be gentler on the eye surface than currently available BAK-preserved latanoprost solutions.

The effect of phenylephrine hydrochloride 2.5 % and sodium hyaluronate solution on visual functions and accommodation in children with myopia and its local tolerability

Purpose: to evaluate visual functions, accommodation, and local tolerance in children instilled with Phenylephrine hydrochloride 2.5 % and sodium hyaluronate solution (Stelphrin Supra). Material and methods. 30 children (60 eyes) aged 8 to 12 (ave. 10.04 ± 0.24) with low (28 eyes) and moderate (32 eyes) myopia (ave. -2.96 ± 0.17 D) were tested. Refractometry, subjective and objective accommodation, optical biometry, anterior corneal surface examination, Norn test, and polling were performed prior to one-time instillation, 30 minutes after it, and after 1 month of daily bedtime instillations of Stelphrin Supra. Results. We noted a significant decrease in the tone of accommodation in the open field by 90 % from the initial value, an approximation of the nearest point of clear vision by 27 %, an increase in the volume of absolute accommodation by 57 % and the objective amplitude of accommodation by 20 %, which indicates an increase in the accommodation ability. The pupil width increased 30 minutes after a single instillation of Stelphrin Supra, which coincided with an increase in the relative accommodation reserve by 25 % from the initial one. After a month, the pupil width significantly decreased, and the positive relative accommodation reserve decreased to a level only 12 % higher than the original one. Tear film break time significantly increased by 0.89 sec, singular spot stainings disappeared in 2 out of 6 patients, lacrimation — in 6 out of 10, pain — in 1 out of 2, blurring in 4 out of 6, feeling of “sand” — in 7 out of 9 patients who had these symptoms before instillations. Conclusion. Regular instillations of Stelphrin Supra reduce the habitual tone of accommodation, increase the accommodation ability, and improve the condition of the eye surface.

Intrascleral Prosthesis in a Dog - Evisceration and Implantation

Background: There is no hope of preserving vision at the terminal stage of glaucoma, and surgical treatment is indicated in these cases. Among the various surgical techniques used, eye evisceration with implantation of an intrascleral prosthesis provide the best cosmetic results. Even though eye evisceration with prosthesis implantation represents an excellent treatment option for terminal glaucoma, reports on the use of this technique in dogs are scarce in the current literature. The aim of this work is to report a case of a dog with end-stage glaucoma subjected to eye evisceration surgery and implantation of an intrascleral prosthesis. Case: A 7-year-old bitch mixed breed with a history of glaucoma secondary to uveitis with no response to medical therapy was referred to the Ophthalmology service of the University Veterinary Hospital of Coimbra (HVUC), Portugal At the ophthalmic examination, the glaucomatous left eye was buphthalmic, with congested episcleral blood vessels, mydriasis, and posterior luxation of the lens; there was no response to threat or obfuscation, no direct and consensual pupillary reflex, nor pupillary reflexes to chromatic light. The intraocular pressure (IOP) was 55 mmHg, and the Schirmer’s tear test (STT-1) result was 19 mm/min. Ophthalmoscopy revealed attenuated retinal blood vessels and a pale optic papilla with mild excavation. The right eye was functional, with all parameters assessed on examination and by tests within the normal ranges for the species. An ultrasound examination of the left eye confirmed the presence of posterior luxation of the lens and buphthalmia in the absence of intraocular neoplasm. In view of the patient’s history and results of the clinical examinations, a surgical approach was indicated to treat the glaucomatous eye. The patient’s tutor requested a surgical procedure that produced a more natural aspect; therefore, the procedure chosen was evisceration, with implantation of an intrascleral prosthesis. The prosthesis diameter chosen was 2 mm greater than the horizontal diameter of the cornea of the functional eye. After evisceration, a black spherical silicone prosthesis of 20 mm in diameter was implanted through a scleral incision. The eye surface was protected with a nictitating membrane flap. In the postoperative period, the cornea exhibited areas with neovascularization, pigmentation, and fibrosis, with a final aspect of gray to black in color. A reduction in tear production was also observed, with no other lesions on the eye surface or major complications. Discussion: Causes of secondary glaucoma include uveitis, disorders of the lens, and neoplasms, among other alterations. Glaucoma can cause clinical signs such as buphthalmic eyes, congestion of the episcleral blood vessels, and increased IOP with nonresponsive mydriasis. The presence of severe degenerative retinal alterations, such as atrophy and excavation of the optic nerve, causes irreversible loss of vision. Surgical treatment is indicated for end-stage glaucoma cases. Eye evisceration with implantation of a prosthesis involves replacement of the intraocular contents by a silicone sphere 1-2 mm larger than the healthy contralateral eye. Protection of the eye surface may be provided using additional procedures such as the nictitating membrane flap. The scleral incision may reduce corneal sensitivity and, consequently, reduce the tear reflex and cause a reduction in STT-1 values. After implantation of the prosthesis, the cornea may exhibit neovascularization, edema, fibrosis, and pigmentation; these are considered expected corneal reactions in the postoperative period. This surgical technique allows treatment of sore and blind eyes, and its results are more aesthetically pleasant compared to other procedures. Preservation of the eyeball with implantation of the prosthesis produced an excellent aesthetic result, with an appearance very close to natural in the case presented here. Keywords: surgery, glaucoma, intraocular prosthesis, silicone. Título: Prótese intraescleral em um cão - evisceração e implantaçãoDescritores: cirurgia, glaucoma, prótese intraocular, silicone.

РАСПРОСТРАНЕННОСТЬ СИНДРОМА СУХОГО ГЛАЗА СРЕДИ СТУДЕНТОВ МЕДИЦИНСКОГО УНИВЕРСИТЕТА В ЗАВИСИМОСТИ ОТ РАЗЛИЧНЫХ ФАКТОРОВ РИСКА

Abstract. Dry eye syndrome is widespread, with an incidence ranging from 5% to 50%, reaching up to 75% in some populations. The number of patients with this pathology is growing every year, while there is a tendency to increase in the incidence at a young age. Aim of the study. To estimate the frequency of DES among medical university students depending on various risk factors. Materials and methods. 52 students of medical university participated in extensive ophthalmic investigation, the median age was 22.8 ± 2.6 years. The OSDI (ocular surface disease index) questionnaire is used to evaluate subjective symptoms of dry eye syndrome. Risk factors for the development and progression of DES were registered: long-term wearing of personal protective equipment (PPE) for respiratory organs and the eye surface, wearing of soft contact lenses, keratorefractive surgery, and diseases of eye and blepharon in past medical history, duration of electronic devices use. Results. The OSDI questionnaire revealed the presence of DES in 56% of the subjects: mild — in 38%, moderate — in 12%, severe — in 6%; the tear film break-up time (TFBT) revealed the presence of DES in 48%. The presence of at least one DES risk factor was found in 71% of students, two factors — in 26.9%, and three or more — in 13.5%. Long-term computer use (50%), prolonged wearing of PPE for respiratory organs and the eye surface (30.7%) and wearing soft contact lenses (19.2%) were the most common. A relationship between the presence of risk factors and the prevalence of DES has been established: according to OSDI questionnaire the prevalence of DES is greater than 30% in persons with risk factors, and according to TFBT is greater than 14%. Conclusion. The revealed high incidence of DES among medical students is a result of scientific and technological progress (computerization in all areas including education), current epidemiological situation (wearing of personal protective equipment) and noticeable increase in the number of ophthalmological patients who need vision correction (with soft contact lenses or keratorefractive surgery). The presence of these risk factors reinforces already existing increasing trend in the prevalence of DES.

Cytotoxicity evaluation of a novel latanoporst 0.005% nanoemulsion

AbstractPurposeTo evaluate the cytotoxicity of a new Latanoprost Benzalkonium chloride (BAK)‐free nanoemulsion and to compare it with a Latanoprost solution containing BAK.MethodsNormal Human Conjunctival epithelial cells (IOBA‐NHC) were incubated for 15, 30, and 60 minutes with 1:6 dilutions of either latanoprost solution containing BAK (LSc), (latanoprost 0.005%, BAK 0.02%, Xalatan, Pfizer) or latanoprost nanoemulsion (LNe), (latanoprost 0.005%, potassium sorbate 0.18%; Louten Emulsion, POEN). Cytotoxicity was determined by MTT assay. Cell death was measured by flow cytometry using annexin V‐FITC and propidium iodide.ResultsCytotoxicity evaluation: the values of cell viability and proliferation obtained from cells exposed to LNe were between 80 and 90% relative to control group, whereas values obtained from cells exposed to LSc were around 30% relative to control group at all study times (p &lt; 0.05 at 15 and 30 minutes; p &lt; 0.01 at 60 minutes).Cell death evaluation: the percentage of viability was significantly lower in cells exposed to LSc compared with those incubated with LNe at all study times (p &lt; 0.05 at 15 and 30 minutes; p &lt; 0.01 at 60 minutes). Viability of cells exposed to LNe was higher than 90% at all study times, whereas there was a time‐dependent decrease in cells exposed to Lsc. The percentage of viable cells in the LNe group was comparable to the viability of control group (93.1%) at all study times. No statistical differences between groups reached in early apoptotic cells. A significant increase of late apoptosis and necrosis cells were observed at all study times for those incubated with Lsc (p &lt; 0.05; p &lt; 0.01 at 30 and 60 minutes).ConclusionsThe new latanoprost nanoemulsion is significantly less cytotoxic on human conjunctival cells than LSc. It suggests that the new formulation could be gentler on the eye surface than currently available BAK preserved latanoprost solutions, with levels of cytotoxicity equivalent to control.

МИТАЦИОННОЕ МОДЕЛИРОВАНИЕ ТЕМПЕРАТУРНОГО РЕЖИМА ПОДШИПНИКОВЫХ УЗЛОВ, ПРИСПОСОБЛЕННЫХ К ТЕРМОНАГРУЖЕННОСТИ

Modern transport and technological machines operate under the seasonality conditions of agricultural operations and significant energy loads. Universal joints of unequal velocity, being part of mechanical power transmissions, work under adverse conditions and limit equipment reliability. It was established that the temperature mode of the bearing assemblies of the universal joints affects the wear rate of their working surfaces. When the temperature in the friction zone increases due to mechanical operation and heating from the environment and adjacent heat sources, boundary friction and temperature conditions exceeding the level of material self-tempering occur. As a result of research, the universal joints (RU199508) were designed to ensure the intensification of cooling its bearing units directly in the maximum heat generation zone during the universal joint operation. Numerical simulation was performed according to the thechinque of calculating radiators for a universal joint with a cross K 040 GOST 13758-89 on needle bearings No. 804704 K5. The results showed the size of the outer surface area that is sufficient for its cooling. When the maximum values of the fracture angle of the universal joint, torque, angular velocity, and efficiency of 0.99 are combined, its bearing units are effectively cooled. It has been found that if the efficiency of the bearing assemblies is less than 0.952, their surface is no longer sufficient to provide efficient cooling and maintain thermal balance conditions in the friction zone. The use of the radiator can increase the heat transfer area by 19%. The radiator ribs fixed on the side surfaces of the yoke eyes with a thickness of 2 mm and a distance of 4 mm and a total area of 166.1 cm2 will ensure the operability of the bearing units. It will remain satisfactory even if their efficiency decreases to 0.943 as a result of mechanical wear.

Prevalence of aqueous deficient dry eye and common ocular surface changes among salt workers

Background: India is the third-largest salt-producing country in the world and Tamil Nadu is the second largest salt-producing state in India. Salt production is one of the most hazardous occupations, which affects the eye and skin primarily. This study was done for assessing the common ocular surface changes among salt workers in Marakkanam, which is a block of Villupuram district in Tamil Nadu. Methodology: It is a cross-sectional study for 2 months among 253 salt workers with minimum exposure of 6 months after taking informed consent. Those with systemic diseases and other ocular surface disorders were excluded from this study. After performing Schirmer's test, an ophthalmic evaluation was done for ocular surface disorders. Results: The prevalence of aqueous deficient dry eye (ADDE) in salt workers is 38.30%. The prevalence of pterygium is 39.50%. The prevalence of pinguecula is 29.64%. Males (46%) are affected more than females (28%) because males are held in the salt pan where sandy and outdoor environments increase the risk of the development of pterygium. Salt pan workers (47%) who work amidst salt crystals and a sandy environment have an increased risk of developing pterygium, than the dry salt workers (24%). Conclusion: ADDE and pterygium are highly prevalent among salt workers. It will also guide the salt workers to know their ocular conditions and the need for a regular ocular check-up to safeguard their eyes.